Manufacture of varnish bases



Patented Jan. 7, 1936 UNITED STATES" PATENT OFFICE I 2,027,338MANUFACTURE OF VARNISH BASES No Drawing. Application June 25, 1935Serial No. 28,353

14 Claims.

This invention relates to the manufacture of varnish bases; and itcomprises methods of making a varnish base useful in making coatingcompositions wherein a phenol is condensed with a polybasic acid andpartially resinified, the product is esterified with a polyhydricalcohol and with the acids of drying oils, the material at this stagebeing sometimes blended or combined with a drying oil; and it furthercomprises varnish bases so obtained and the varnishes obtained bydissolving the base in a volatile vehicle such as coal tar oils, mineralspirits, turpentine, etc.; all as more fully hereinafter set forth andas claimed.

In my prior applications Serial Nos. 526,568 and 586,467, filed March30, 1931 and January 13, 1932 respectively, I have described processesof making new resins from partially resinifled complex phenol-phthalicanhydrid condensation products, and various compositions containing thenew modified resins. In those processes the phenol is condensed withphthalic anhydrid and the product partially resinifie'd. The partiallyresinified condensation product is then reacted with certain reagents toform more complex resins.

This application is in part a division and in part a continuation of thesaid prior applications. It is directed to methods of making particularvarnish bases, to the bases and to varnishes made therefrom. I

In the present invention partially resinified complex phenol-phthalicanhydrid condensation products prepared as described in the priorapplications are esterified with glycerin and with fatty acids of adrying oil, to form new types of varnish bases characteristicallydifferent from those now in use in making oil varnishes. v The newvarnish bases have, in part, the char- 40 acteristics of resinousglycerids capable of heathardening and in part the characteristics ofoily glycerids of drying oils,'but are unitary bodies of complex nature.No fractionation or segregation can be obtained with solvents. Theirsolubility in a wide range of solvents and other features of theirbehavior indicates the presence of a new resin molecule of, greatcomplexity. The varnish bases of the prior art are rarely soluble inmany solvents of different chemical types.

.With the materials of this invention certain dimculties in preparingoil type varnishes with prior varnish bases are avoided or eliminated.

Better varnishes are easily made; varnishes either long or short in oil.

In the present invention the stated materials are processed by acorrelated series of steps. A phenol is condensed with the phthalicanhydrid in the presence of a catalyst, ordinarily aluminum chlorid; 2mols of phenol being usually condensed with about 1 mol of phthalicanhydrid. Advantageously the phenol is melted and the phthalic anhydridadded to the liquid. When a homogeneous solution is obtained, thecatalyst is slowly added. With aluminum chlorid the temperature rises toabout 130 C. because of 10 vigorous reaction. After the reaction iscomplete, the reaction product is kept at about C. until it thickens anda partially resinifled mass is obtained. Reaction with glycerin anddryin w oil acids follows.

In an advantageous procedure glycerin is added to a molten mixture ofthe acids with the partially resinifled material. at between 200 and 250C., until esterification is effected and a new resin of the desiredproperties is obtained; till a sample cooled to room temperature showsthe required consistency, hardness, etc. 5 j

All the varnish bases obtainedin the described method are of the same vvariations in proportions of ingredients give some variation in theproduct. All are soluble in benzol, toluol, esters, ketones andturpentine, givingclear uniform solutions directly applicable asvarnishes. Most of the varnish bases are-also soluble in mineral spiritssuch as the commercial turpentine substitutes. A They can be blendedwith drying oils, such'as linseed oil and perilla oil. In blending, itis advantageous to add the drying 011 immediately after the introductionof the glycerine. In so doing homogeneous compositions are obtained fromwhich drying oil cannot be separated by the fractionating action ofsolvents.

In qualifying the varnish base with drying oil it is advantageous to mixthe partially resinified material made' from phenol and phthalicanhydrid with the fatty acid and bring the mixture to about 200 C. Atthis time the glycerin is slowly added while continuing the heating.When a clear mixture results, preheated drying oil is added. It isadvantageous to have the clear mixture at about 250 (Lv at the time ofthe addition. Heating at 250 C. is continued until a portion of the hotliquid cooled to the ordinary temperature and outwith an equal weight ofmineral spirits gives ayarnish having a viscosity between 3 and 4minutes by test in a No. 4 Ford cup at 25 C.

In making the varnish bases to secure a neutral Product it is sometimesadvantageous to use Heating is continued,

general :properties but somewhat more glycerin than the calculatedamounts.

With 100 parts of phenol phthalic condensation product, and between 50and 100 parts of fatty acid and 40 to 50 parts of glycerin, resinousvarnish bases having satisfactory acid number can be obtained withoutdifficulty. Usually the acid number should be between 10 and 15.

With higher ratios of fatty acid, the resins are more oil-like incharacter. By adjusting the ratios more or less plastic resins may beobtained at will. A variety of products may be obtained, each useful forspecial purposes.

The ratio and the type of drying oil may vary. To obtain long oilvarnishes, the amount of drying oil is increased. The sum of the fattyacid and of the drying oil determine the type of varnish base obtained;and are correlated to produce what may be wanted.

Good commercial varnish bases are produced with component ratios withinthe following range:

Phenol-phthalic anhydrid condensa- Parts tion product 100 Glycerin 40 to55 Fatty acid 40 to 100 Drying oil 20 to 150 The plasticity of the resindepends partly upon the extent of the resiniflcatlon obtained during theheating at 200 C. or above. Reactive residual hydroxyl groups in thephenol phthalic condensation product play a part in this resinificationoperation. The consistency of the resin or varnish base is therefore notsolely a matter of adjusting the ratio of the esterifying reagents.

The present invention is quite flexible in meeting demands for varnishbases having special combinations of properties.

In making the phenol phthalic anhydrid condensation product, in lieu ofphenol itself and of phthalic anhydrid, other phenols and other dibasicaromatic carboxylic acids may be used. The phthalic anhydrid may bereplaced with phthalic acid or by another suitable polybasic carboxyllcacid of cyclic structure. The carbolic acid (phenol) may be replaced bysimilar phenolic bodies such as cresols or xylenols. Also, in lieu ofaluminum chlorid, as the catalyst, other condensing catalysts may beused, such as the tin chlorids, ferric chlorid, etc. As stated in mycopending application Ser. No. 526,568, zinc chlorid may be used as thecatalyst. In other words, in my present processes, the condensationcatalyst used in making the phenol-polybasic acid condensation productmay be a catalyst of the class consisting of the chlorid of aluminum,iron, tin and zinc.

The partially resinified phenol phthalic anhydrid condensation productsare materials of rather indefinite constitution. They probably contain,among other things, para-dioxytriphenyl-carbinol-o-carboxylic acid or alactone of that compound or, and probably, both the acid and lactone.This, unlike phthalic acid is mono-basic. The exact nature of thecomplex reaction products is not here material, it being sufficient thatthey are convertible by the present methods into new and valuablevarnish bases.

Other high boiling polyhydric bodies may be substituted for theglycerine, in Whole or in part, but glycerin is satisfactory for mostpurposes. The glycols may be used but are not better.

fVarious fatty acids, both drying and non-drying, may be used, such asthose of castor oil, linseed oil, perilla oil or soya bean oil. Acids ofdrying oils are ordinarily used. Sometimes rosin, resin acids andresinous materials which are somewhat acid may be employed inconjunction with and in addition to the fatty acid. Resin 5 acids fromsoft manila copal are advantageous.

The following examples in which the parts are parts by weight areillustrative embodiments of this invention.

Example 1 10 Approximately two molecules of ordinary phonol are reactedwith 1 molecule of phthalic anhydrid in the presence of freshingsublimed aluminum chlorid asa catalyst; 190 parts of phenoi being heatedto a temperature of to C. and 148 parts of phthalic anhydrid added. Whena homogeneous solution is obtained, 10 to 50 parts of aluminum chloridare slowly added. A violent reaction occurs and the temperature rises to20 about l20-l30 C. After completion of the violent reaction, themixture is held at 120 C. until a gelatinous mass is obtained.Approximately two hours are required.

Example 2 To parts of the condensation product of Example 1 there isadded 90 parts of linseed oil acids and the mixture slowly heated to 200C. in about 45 minutes. To this hot mixture, 48 30 partsof glycerine areslowly added,while continuing the heating. After all the glycerin isadded the temperature is gradually brought to 250 C. Approximately onehour is required. The mixture is held at about 250 C. until a clearproduct re- 35 sults having a viscosity about that of heavy bodied standoil. Some esterification is effected during this time. To the clearproduct at 250 C., 100 parts of preheated linseed oil (200 C.)- isgradually added, the mixture being heated and 40 stirred during thisaddition. After all the linseed oil has been added the mixture isfurther heated at about 250 C. until a sample cooled to room temperatureis absolutely clear and shows the desired properties such as specificgravity, vis- 45 cosity, color, acid value, etc. Between 6 and 10 hoursis usually required.

Example 3 In making a varnish, the varnish base, after 50 complete orpartial cooling, is cut with an equal weight of mineral spirits (boilingpoint 300-370 F.) The 50 per cent solution thus obtained is an excellentvarnish and has a viscosity of one minute, 20 seconds when tested in aNo. 4 Ford cup at 25 C. The varnish is long in oil. It gives coat ingswhich dry tack-free in about 10 to 12 hours. The air-dried coating maybe baked at C. for three hours. 60

This varnish may be pigmented in the usual way with the usual pigmentsto give good enamels.

Example 4 In making a varnish base particularly adaptable in producingbaked oil varnishes, 100 parts of the product formed by the processof'Example 1 are esterified with 90 parts of the fatty acids of castoroil, linseed oil, perilla oil or soya oil and with 50 parts of glycerin.The reaction product 70 and the fatty acid are first mixed together andthe mixture heated slowly to about 200 C. and kept at this temperatureuntil the mixture is almost clear. Then the glycerin is slowly addedwhile continuing the heat. A clear product is obas being, in largemeasure, due to the fact the phthalic acid is converted into somethingsaponiflcation tained having a viscosity about the same as that of heavybodied stand oil (polymerized" linseed oil). Upon further heating thisis-converted into a plastic resinous mass. 7

Example 5 To prepare a varnish base short in oil, the procedure ofExample 2 may be used, except that the respective amounts of linseedoil'acids and of linseed oil are reduced.

A mixture of 100 parts of the product of Ex= ample l and 60 parts oflinseed oil acids are gradually heated to 200 C. and stirred until auniform mix is obtained. About minutes are required. Then 40 parts ofglycerin are gradually stirred into the hot mixture. When all theglycerin has been added the mixture is heated to about 250 C..'

and is held at that temperature until a clear product having a viscosityabout that of a heavy bodied stand oil is obtained. About 4 hours arerequired. During this time most of the esterification iseifected, butthe complete esterification and the resiniflcation desired are postponeduntil after the addition of the drying oil..

To the hot partially esteriiied material are added 15 parts of preheatedlinseed oil. This mixture is held at about 250 C. until the desiredreactions and resinifi'cation are obtained. About out hour is requiredto obtain a clear, uniform resin upon cooling to room temperature. Whena sample so cooled shows the desired end point has been reached, theheating is stopped.

The resinous varnish base is then partially cooled to about 150 C. andcut with toluol or other suitable varnish solvents.

This resin, short in oil, hen cooled to room temperature is a non-tackymaterial. It is soluble in coal tar hydrocarbons.

The new varnish bases have many advantages over the resins prepared inordinary ways. from phthalic acid, glycerin and fatty acids, with orwithout drying oils. They are easier to prepare,

the solubilities are better, the products are uniform, giving clear,homogeneous solutions with out part kicking out and the varnish filmsmade in using the varnish are of better quality. These new results andthe betterment I attribute that else; the new products do not have thesame constitution or properties as those in which phthalie "'id oranhydrid is used as such.

Resinous bodies madeby reaction of phthalic anhydrid, glycerin and afatty acid of some kind are well irnown and commercially used. Theyharden iii the usual A, B, resins, however, on treatment withcausticsoda are hydrolyzed, giving sodium phthalate and a sodium soap ofthe fatty acid. In the resinous product of the present invention this isnot true; does not givea phthalate. The

identity of the phthalicacild'sgroup disappears in the processhereinbefore ribed.

C succession. All these product and between WhatrI claim is: i. In themanufacture of varnishes, the improvement in making a varnish base whichcomprises condensing about 2 mols of a phenol with 1 mol of an anhydridof an aromatic dicarboxylic acid in the presence of an inorganiccatalyst, of the class consisting of the chlorides of aluminum, iron,tin and zinc, to form a phenoi-polybasic acid condensation product,fusing together the said condensation product and the fatty acid of afatty oil, adding sufllcient giycerine to the molten mixture to ,produceesteriflcation, and heating to at least 200 C. until esteriflcation andresiniiication occur, a resinified material being obtained upon cooling.

2. The process of claim 1 wherein a drying oil is added to the saidreaction mixture before the resinified material is obtained by saidheating to at least 200 C. I

3. In the manufacture of step which comprises esterifying aphenolphthalic condensation product with glycerine and with a fatty acidof a fatty oil, said phenolphthaiic condensation product being one ob--tained by condensing about 2 mols of a phenol 25 with l moi of phthalicanhydrid in the presence of an inorganic catalyst of the classconsisting of the chlorides of aluminum, iron, tin and zinc.

4. In the manufacture of varnish resins the steps which comprise addingan aromatic dicarboxyiic acid anhydridto a molten phenol in a molecularratio of approximately 1:2 of anhydrid to phenol, adding aluminumchloride to the homogeneous solution thus obtained, permitting the firstviolent reaction to subside and then heating the reaction mixture untilthe reaction is substantially complete and a gelatinous mass isobtained, to produce a phenol-polybasic acid condensation product,fusing together with said c'ondensation product a adding suflicientpolyhydric alcohol to the molten mixture to produce esterification, andfurther heating the reaction mixture to between 200 and 250 C. untilesterification and resinification occur, and a resinifled materialhaving an acid number between 10 and 15 is obtained, said resinifiedmaterial being an improved varnish base and soluble in mineral spiritsand other varnish solvents. p

5. The process of claim 4 in which said aromatic dicarboxylic acidanhydrid is phthaiic anhydrid.

varnish bases, the 20 fatty acid of a drying oil,

6. The process of claim 4 wherein said polyhydric alcohol is glycerine.

7. The process of claim 4 wherein said fatty acid is the fatty acid oflinseed oil.

8. As an improvement in the manufacture of useful complex resins fromphenols, phthalic anhydrid, glycerine and the fatty acids of a dryingoil, the steps which comprise heating approximately 190 parts of phenolbetween 80 and 90 0., adding about 148 parts of phthalic anhydrid to theheated phenoL. continuing the heating until a homogeneous solution isobtained, slowly adding between- 10 to parts of aluminum chloride to thesaid solution, permitting the first violent reaction to subside and thenfurther heating the reaction mixture to about 120 C. until the reactionis substantially completeand recovering the condensation product thusobtained, fusing together about 100 parts of said condensation 40 to 100parts of said fatty acids, adding to the molten mass so obtained between40 and parts of glycerine and further heating the mixture to about 250C. until a clear non-tacky esterified resin is obtained upon 0001- mg.

9. The process of claim 8 wherein said fatty acids are the fatty acidsof linseed oil.

10. The process of claim 8 wherein preheated drying oil, preheated toabout 240 0., is added to the said clear molten resin prior to thestated further heating, between 20 and 150 parts ofdrying oil being soadded and the mixture of oil and resinous ester being then heated toabout 250 C. until a uniform, homogeneous varnish base is obtained, saidvarnish base being soluble in a wide range of varnish solvents.

11. In the manufacture of varnish bases, the improved process whichcomprises condensing a phenol with an aromatic polybasic carboxylic acidwith the aid of aluminum chlorid to produce a phcnol-polybasic acidcondensationprodnot containing reactive phenolic groups and containingphenol combined with the polybasic acid in approximately the molar ratioof 2:1, partially resinifying the said condensation product, by heatingto approximately 120 0., fusing the said partially resinifiedcondensation product with a fatty acid of a fatty oil, adding glycerineto the molten mixture in amount sufiicient to esterify the same, furtherheating the mixture to effect some esterification, adding a drying oiland heating the reaction mixture to at least 200 C. until a. unitarycomposite varnish base is obtained.

12. The process of claim 11 wherein the hot varnish base is partiallycooled and then reduced with a varnish solvent.

13. As an improved varnish base, the clear non-tacky resinous materialobtained by the process of claim 11, said resinous material being asubstantially neutral ester comprising a drying oil combined with aphenol-polybasic acid condensation product esterified with a fatty acidand with glycerine, said varnish base being soluble in mineral spiritsand other varnish solvents and yielding when dissolved in said solventsto produce a 50 per cent solution thereof, a varnish 15 having aviscosity between 1 and 5 minutes in a No. 4 Ford cup.

14. As a new product, useful in making varnish and other coatingcompositions, the resinified product obtained by the process of claim12, said product being a resinified reaction product of aphenol-polybasic acid condensation product with a polyhydric alcohol anda fatty acid of fatty oil, said resinified product being a unitarymaterial uniformly soluble in drying oils and in varnish solvents suchas mineral spirits, coal tar hydrocarbons and the like.

ADOLF HECK.

